115 Classification, Clinical Manifestations, and Evaluation of Disorders of Hemostasis Flashcards
The most frequent acquired disorder in hemostasis
Thrombocytopenia
TRUE OR FALSE
If hypersplenism is the sole cause of a hemostatic disorder, it is rarely severe enough to cause pathologic bleeding.
TRUE
If hypersplenism is the sole cause of a hemostatic disorder, it is rarely severe enough to cause pathologic bleeding.
Typical patterns of bleeding
Unprovoked hemarthroses and muscle hemorrhages:
Unprovoked hemarthroses and muscle hemorrhages: hemophilias
Typical patterns of bleeding
Mucocutaneous bleeding- epistaxis, gingival bleeding, menorrhagia:
Mucocutaneous bleeding- epistaxis, gingival bleeding, menorrhagia: qualitative platelet disorders, thrombocytopenia, or von Willebrand disease
Obtaining objective confirmation of the subjective information conveyed in the bleeding history is valuable. Objective data include:
- Previous hospital or physician visits for bleeding symptoms
- Results of previous laboratory evaluations
- Previous transfusions of blood products for bleeding episodes
- A history of anemia and/or previous treatment with iron
The most commonly used herbals that can cause platelet dysfunction and induce bleeding.
Ginkgo biloba and ginseng
A nutrition history should be obtained to assess the likelihood of:
- Vitamin K deficiency, especially if the patient also is taking broad-spectrum antibiotics
- Vitamin C deficiency, especially if the patient has skin bleeding consistent with scurvy (perifollicular purpura); and
- General malnutrition and/or malabsorption.
Tissues that have an increased local fibrinolytic activity:
- Urinary tract
- Endometrium
- Mucous membranes of the nose and oral cavity
These sites are particularly likely to have prolonged oozing of blood after trauma in patients with hemostatic abnormalities
Bleeding resulting from defects in fibrin crosslinking (factor XIII deficiency), or fibrinolytic defects may often manifest as:
Delayed bleeding after trauma
TRUE OR FALSE
Bleeding isolated to a single organ or system (eg, hematuria, hematemesis, melena, hemoptysis, or recurrent nosebleeds) is less likely to result from a hemostatic abnormality than from a local cause
TRUE
Bleeding isolated to a single organ or system (eg, hematuria, hematemesis, melena, hemoptysis, or recurrent nosebleeds) is less likely to result from a hemostatic abnormality than from a local cause
Example of blood vessel disorders that may cause bleeding
Hereditary hemorrhagic telangiectasias, Cushing disease, scurvy, or Ehlers-Danlos syndrom
Many primary dermatologic disorders also have a purpuric or hemorrhagic component and must also be considered in the differential diagnosis
Mode of inheritance of hemophilia A or B:
Sex-linked pattern
Mode of inheritance of most forms of von Willebrand disease:
Autosomal dominant
Mode of inheritance of pattern typical for all other coagulation factor deficiencies, inherited platelet disorders, and the rare, severe (homozygous), type 3 von Willebrand disease
Autosomal recessive
Population genetic information may be helpful; for example, the higher prevalence of ________ deficiency in Ashkenazi Jews.
Factor XI deficiency
One of the most common signs of platelet disorders and von Willebrand disease.
It also is the most common symptom of hereditary hemorrhagic telangiectasia.
Epistaxis
Epistaxis is not uncommon in normal children, but it usually resolves before puberty.
Dry-air heating systems can provoke epistaxis even in otherwise normal individuals.
TRUE OR FALSE
Bleeding confined to a single nostril more likely results from a local vascular problem than a systemic coagulopathy.
TRUE
Bleeding confined to a single nostril more likely results from a local vascular problem than a systemic coagulopathy.
TRUE OR FALSE
Excessive bruising is more common in men than women.
FALSE
Excessive bruising is more common in women than men.
Moreover, women frequently note that the severity of their bruising varies with the phase of their menstrual cycle, although the most severe phase of the cycle may differ per woman.
Red bruises on the extensor surfaces of the arms and hands indicate loss of supporting tissues, as occurs in :
Cushing syndrome, glucocorticoid therapy, senile purpura, and damage from chronic sun exposure
Jet-black bruises may be caused by :
Warfarin-induced skin necrosis and similar disorders
A hereditary disorder characterized by local angiodysplasia, mostly present in the skin, mucous membranes, and often in organs such as the lungs, liver, and brain .
It may lead to nose bleeding or acute and chronic digestive tract bleeding
Also manifest with easy bruising
Rendu-Osler-Weber disease
Manifested by distensible skin or extraordinary ligament laxness and in patients with hyperflexibility of the thumb
Also manifest with easy bruising
Ehlers-Danlos syndrome
TRUE OR FALSE
Molar extractions are greater hemostatic challenges than extractions of other teeth.
TRUE
Molar extractions are greater hemostatic challenges than extractions of other teeth.
TRUE OR FALSE
Hemoptysis almost often is the presenting symptom of a bleeding disorder and is common even in patients with serious bleeding disorders.
FALSE
Hemoptysis almost never is the presenting symptom of a bleeding disorder and is rare even in patients with serious bleeding disorders.
Melena, hematemesis, like hemoptysis, almost never is the presenting symptom of a hemostatic disorder
TRUE OR FALSE
Hematuria is rarely the presenting symptom of a hemostatic disorder except for the hemophilias
TRUE
Hematuria is rarely the presenting symptom of a hemostatic disorder except for the hemophilias
Rectal bleeding in individuals with normal hemostasis most often results from:
Hemorrhoids
Menorrhagia is common in women with platelet disorders and von Willebrand disease.
In general, menstrual bleeding is considered excessive if the patient indicates she has heavy flow for more than _______ days or total flow for more than _________days.
More than three days or total flow for more than seven days
However, an objective distinction between menorrhagia (loss of >80 mL of blood per period) and normal blood loss can only be made by a visual assessment technique using pictorial charts of towels or tampons.
Childbirth poses a considerable hemostatic challenge. Consequently, patients with bleeding disorders commonly manifest excessive bleeding during or after labor, necessitating blood transfusion.
An exception is:
Mild and moderate von Willebrand disease
There is vast increase in von Willebrand factor during pregnancy.
Habitual spontaneous abortions raise the possibility that the patient has a:
Quantitative or qualitative abnormality of fibrinogen, factor XIII deficiency, or the antiphospholipid syndrome
Are the hallmark abnormality in the hemophiliac; they are rare in other disorders except in severe factor VII deficiency and type 3 von Willebrand disease
Hemarthroses
Characteristic of factor XIII deficiency and afibrinogenemia
Bleeding from the umbilical stump
Range from pinpoint erythematous dots that blanch with pressure to classic cherry angiomata ranging in size up to several centimeters
Telangiectasias
More florid lesions that characteristically affect the vermilion border of the lips and the tongue (including the underside of the tongue)
Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease)
Found in patients with chronic liver disease have a more splotchy and serpiginous appearance
Concentrated on the shoulders, chest, and face
Spider telangiectasias
A prolonged aPTT as a sole abnormality can be caused by:
- Deficiency of factor VIII, IX, XI, or XII;
- Presence of heparin;
- Presence of an inhibitor, which can be either factor specific, such as an antibody against factor VIII, or factor nonspecific, such as the presence of heparin or a lupus anticoagulant
A prolonged PT as the sole finding can indicate
- Factor VII deficiency
- Mild vitamin K deficiency
- Presence of an inhibitor
Abnormalities of both PT and aPTT may indicate
- Deficiency of fibrinogen, prothrombin, factor V or factor X
- An inhibitor to one of these factors
- A combined deficiency of coagulation factors
Used to distinguish between a deficiency state and the presence of an inhibitor
Mixing studies
Repeating the abnormal test, the PT and/or aPTT, using a 1:1 mixture of the patient’s plasma and normal plasma
If the mixture normalizes the prolonged PT or aPTT, a deficiency state is likely
If the mixture still yields a significantly prolonged PT or aPTT, an inhibitor probably is present.
TRUE OR FALSE
Some inhibitors, such as antibodies to factor VIII, require time to inhibit the factor VIII activity in the assay, whereas other inhibitors, such as lupus anticoagulant or heparin, do not.
Consequently, incubating the mixture for four hours at 32C before performing the coagulation assay is desirable.
FALSE
Some inhibitors, such as antibodies to factor VIII, require time to inhibit the factor VIII activity in the assay, whereas other inhibitors, such as lupus anticoagulant or heparin, do not.
Consequently, incubating the mixture for one or two hours at 37 C before performing the coagulation assay is desirable.
Tests done if none of the initial test results (PT, aPTT, and platelet count) is abnormal and the patient exhibits bleeding manifestations
Ristocetin cofactor (RCF) or von Willebrand factor activity and examination of the blood film
TRUE OR FALSE
The bleeding time is not used anymore because the test is highly operator and situation (eg, room temperature, skin circulation) dependent and is not sufficiently reliable to be useful in the diagnostic process.
TRUE
The bleeding time is not used anymore because the test is highly operator and situation (eg, room temperature, skin circulation) dependent and is not sufficiently reliable to be useful in the diagnostic process.
Instead, many laboratories have introduced the platelet function analyzer to detect qualitative defects in primary hemostasis.
Characterized by presence of giant platelets on blood film
Bernard-Soulier syndrome
Useful for distinguishing type 2B and platelet-type von Willebrand disease from the other types of von Willebrand disease
Ristocetin-induced platelet aggregation test
In type 2B and platelet-type von Willebrand disease, an enhanced response to low concentrations of ristocetin is observed, whereas in the other types of von Willebrand disease, a decreased response is found.
Characteristics of total absence of platelet aggregates in a blood film prepared from nonanticoagulated blood and absent clot retraction
Glanzmann thrombasthenia
Thrombin time (time for plasma to clot after adding thrombin) is prolonged in:
(a) afibrinogenemia, hypofibrinogenemia, and dysfibrinogenemia
(b) the presence of heparin
(c) disseminated intravascular coagulation (DIC) causing increased levels of fibrin(ogen) degradation products, which inhibit fibrin monomer polymerization
(d) patients with amyloidosis and an immunoglobulin inhibitor of thrombin
The preoperative risk assessment of hemostasis is based on:
- Bleeding history
- Physical examination
- The underlying disorder if any,
- The type and site of surgery that is planned
- The results of basic hemostatic tests (PT, aPTT, platelet count)
- In addition to the extent of the surgical trauma, the magnitude of the fibrinolytic activity at the surgical site must be considered.
- The ability to institute local hemostatic measures should be considered.
Surgeries expected to induce hemostatic defects
Open heart surgery or brain surgery
Surgeries with sites of local fibrinolysis
Prostatectomy, tonsillectomy, oral or nasal surgery
Surgeries where local hemostatic control is ineffective
Liver, lung, or kidney biopsy
PBS: giant platelets and Dohle bodies in leukocytes
May-Hegglin and other MYH9 platelet syndromes
PBS: moderately enlarged platelets
Immune thrombocytopenia or other conditions associated with shortened platelet survival
PBS: small platelets
Wiskott-Aldrich syndrome
PBS: schistocytes and burr cells
Hemolytic uremic syndrome and thrombotic thrombocytopenic purpura and occasionally in DIC
The activities of factors II, V, VII, and X usually are determined in _________ assays, whereas the activities of factors VIII, IX, XI, and XII, prekallikrein, and high-molecular-weight kininogen are measured in ________ assays.
Factors II, V, VII, and X : PT-based assays
factors VIII, IX, XI, and XII, prekallikrein, and high-molecular-weight kininogen: aPTT-based assays
The plasma level of fibrinogen most commonly is measured by
Assessing the time required for thrombin to clot the patient’s diluted plasma (Clauss method)
Used in measuring factor XIII activity
Assays of transglutaminase activity
Simple qualitative test based on dissolving a fibrin clot in 5 M urea
Measures the ability of the patient’s plasma to support the agglutination of a suspension of formaldehyde-fixed normal platelets by ristocetin
RCF activity
Most common cause of prolonged aPTT on mixing studies
Presence of heparin in the sample
This cause can be verified by finding a prolonged thrombin time on a test of the patient’s plasma that is corrected with toluidine blue or other agents that neutralize heparin.
TRUE OR FALSE
With lupus anticoagulant, the PT usually is less prolonged than is the aPTT, and aPTT reagents have markedly different sensitivity to lupus-type anticoagulant depending on the amount of phosphatidyl serine present in each reagent.
TRUE
With lupus anticoagulant, the PT usually is less prolonged than is the aPTT, and aPTT reagents have markedly different sensitivity to lupus-type anticoagulant depending on the amount of phosphatidyl serine present in each reagent.
Originally was designed to quantify factor VIII inhibitors but can be modified to detect other inhibitors of coagulation factors
Bethesda assay
Used to detect qualitative defects in primary hemostasis
Platelet function analyzer
